The present invention relates to a substrate processing system and a substrate processing method for performing a series of processes to several types of substrates such as semiconductor wafers and glass substrates used for liquid crystal displays.
Micro circuit patterns are formed by photolithography in fabrication of glass substrates used for liquid crystal displays (LCD substrates) and semiconductor devices, etc.
A circuit pattern is formed in photolithography by applying a resist on a substrate such as an LCD substrate and a semiconductor wafer and forming the resist film followed by exposure to the pattern, development and etching.
Photolithographic systems for handling several wafers have been developed in recent trend of large diameter for semiconductor wafers. A complex processing system capable of resist-application and development, for example, takes out wafers one by one from a cassette into a processing unit in which the wafers are processed one by one, and the processed wafers are returned to the cassette one by one.
A processing time for each of several units in this complex processing system is called one cycle. The system cannot proceed to the next processes until the previous processes are completed in every unit for one cycle.
Therefore, in a complex processing system that transfers a wafer to the next processing unit after the previous process has been completed, a process to be performed by the present unit is susceptible to the process performed by the previous unit, or the present unit has to wait for the completion of the previous processing (called waiting-time consumption).
In a series of processing, such as, baking, cleaning and development performed in this order, the developing process requires a relatively long processing time. Due to long developing process time, a wafer for which the baking and cleaning processes have been completed has to remain in the baking or the cleaning unit to wait for completion of the developing process to the previous wafer. A wafer will be over-baked when it remains in the baking unit for such a long time.
A thermal processing time is precisely controlled in wafer processing recently. Such over-baking for a period longer than a controlled time, however, varies pattern width formed through a resist. Desired patterns thus cannot be formed.
In order to solve the problem discussed above, a purpose of the present invention is to provide a substrate processing apparatus that reduces effects of waiting time unnecessarily consumed (rate controlling) by any processing unit.
The present invention provides a substrate processing system including first to n-th processing units (n=1, 2, . . . , N) each having at least one identical unit for performing first to n-th wafer-processing for given periods t1 to tn, respectively, the processing being performed in order from the first unit to the n-th unit, a plurality of substrates being simultaneously processed by different types of the processing units for one cycle, the system including: a loading/unloading section for taking in and out the substrates; a first transfer section for receiving/transferring the substrates from/to the loading/unloading section and transferring the substrates one by one to each processing unit; and a controller for controlling the first transfer section and the processing units so that each processing unit processes the substrates one by one in accordance with one-cycle time as a standard time, the one-cycle time being the maximum period among periods t1/m to tn/m obtained by dividing the periods t1 to tn by the number xe2x80x9cmxe2x80x9d of the identical units of the first to n-th processing units.
In this substrate processing system according to the present invention, the controller may control the first transfer section and the processing units so that the processing time required for each processing unit corresponds to the one-cycle time. The processing time required for each processing unit may include a pre-transfer time, a net processing time, a post-transfer time and a plurality of waiting times. The waiting times may be allocated before or after one of the pre-transfer time, the net processing time and the post-transfer time in the processing time required for each processing unit.
In this substrate processing system according to the present invention, the controller may control the first transfer section and the processing units so that the processing time required for each processing unit corresponds to division of the one-cycle time by an integer. The processing time required for each processing unit may include at least a pre-transfer time, a net processing time and a post-transfer time. The processing time required for a desired processing unit may further include a waiting time.
In this substrate processing system according to the present invention, the controller may control the first transfer section and the processing units so that the total of the processing times for the successive xe2x80x9cnxe2x80x9d number of processing units equals to one-cycle timexc3x97n. The processing time required for each processing unit may include at least a pre-transfer time, a net processing time and a post-transfer time. The processing time required for a desired processing unit may further include a waiting time.
In this substrate processing system according to the present invention, the processing units may include at least one thermal processing unit. The thermal processing unit may have a heating mechanism and a lift-up mechanism for holding each substrate so that the substrate is distant from the heating mechanism, the thermal processing unit waiting for thermal processing while the lift-up mechanism is holding the substrate as distant from the heating mechanism.
In this substrate processing system according to the present invention, the processing units may include at least one developing unit for developing a resist applied onto each substrate.
In this substrate processing system according to the present invention, the processing units may include at least one exposing apparatus for exposing a resist applied onto each substrate.
This substrate processing system according to the present invention may further include a second transfer section provided as accessible to each of the processing units for transferring each substrate from one of the processing units to another.
Moreover, the present invention provides a substrate processing system including first to n-th processing units (n=1, 2, . . . , N) each having at least one identical unit for performing first to n-th wafer-processing for given periods t1 to tn, respectively, the processing being performed in order from the first unit to the n-th unit, a plurality of substrates being simultaneously processed by different type of the processing units for one cycle, the system including: a loading/unloading section for taking in and out the substrates; a first transfer section for receiving/transferring the substrates from/to the loading/unloading section and transferring the substrates one by one to each processing unit; a second transfer section for receiving/transferring the substrates from/to the processing units; and a controller for controlling the first transfer section, the second transfer section and the processing units, when the substrates are simultaneously processed by the different types of processing units, so that each processing unit processes the substrates one by one within one-cycle time that corresponds at least to either a first total transfer time or a second total transfer time that is larger than the other, the first total transfer time being the total of periods in the one cycle for the first transfer section required for receiving/transferring each substrate from/to the loading/unloading section and transferring the substrate to each processing unit, the second total transfer time being the total of periods in the one cycle for the second transfer section required for receiving/transferring the substrate from/to the processing units.
In this substrate processing system according to the present invention, the controller may calculate the maximum period among periods t1/m to tn/m obtained by dividing the periods t1 to tn by the number xe2x80x9cmxe2x80x9d of the identical units of the first to n-th processing units and sets the maximum among the maximum period, the first total transfer time and the second transfer time as the one-cycle time for controlling the first and the second transfer sections.
In this substrate processing system according to the present invention, at least one of the processing units may be a substrate-receiving unit for receiving and processing each substrate, the controller calculating the total receiving and processing period for the substrate-receiving unit for receiving and processing each substrate and setting the maximum among the total receiving and processing period, the first total transfer time and the second transfer time as the one-cycle time.
This substrate processing system according to the present invention may further include: an exposing apparatus; and a third transfer section for receiving the substrates from the processing units and transferring the substrates to the exposing apparatus, wherein the controller sets the maximum among the first total transfer time, the second total transfer time and a third total transfer time for the third transfer section required for the one cycle as the one-cycle time.
Moreover, the present invention provides a method of processing substrates with first to n-th processing units (n=1, 2, . . . , N) each having at least one identical unit for performing first to n-th wafer-processing for given periods t1 to tn, respectively, the processing being performed in order from the first unit to the n-th unit, a plurality of substrates being simultaneously processed by different types of the processing units for one cycle, the method including the steps of: processing the substrates one by one in accordance with one-cycle time as a standard time, the one-cycle time being the maximum period among periods t1/m to tn/m obtained by dividing the periods t1 to tn by the number xe2x80x9cmxe2x80x9d of the identical units of the first to n-th processing units; and performing processing to each substrate in at least one of the processing units with a waiting time.